When an automatic latching device is used or is not used as part of a boat trailer, the boat needs to be propelled up onto the trailer with sufficient speed and momentum to engage the bow roller or an automatic latching device. The typical approach is to keep the trailer on the loading ramp and the back half under the water. This then requires more speed or momentum for the boat to reach the bow roller or automatic latching device as the boat has to be driven up the incline of the trailer. This in turn causes added wear on the automatic latching device due to the impact force.
It would be an improvement to the typical boat loading procedure when an automatic latching device is used to be able to float the trailer in the water so that less speed and less momentum is required to ramp the boat onto the trailer and engage the automatic latching device. In fact, the boat, while at idle speed, can be loaded onto the trailer and engage the automatic latching device with a minimal impact force. By floating the trailer in the water, the buoyancy of the boat is maintained throughout a majority of the loading process and this further contributes to the fact that there is less of an impact force on the automatic latching device and the boat hull.
However, if low water conditions exist at the loading ramp, the boat trailer wheels can still be in contact with the bottom of the water or the loading ramp surface when the boat trail is in the maximum back-in position and not floating.
By using air springs in the trailer suspension system, the trailer frame is lowered when the air pressure is exhausted and boat keel pressure is applied to the trailer back keel roller.
This can be accomplished by connecting the air spring air supply to the trailer tongue cylinder rod extending air supply. When the trailer tongue cylinder air supply is reversed, so as to lower the hinge and the front portion of the trailer frame, the air springs air supply would be exhausted. A suitable air spring for this application is offered by Firestone under their “SPORT-RITE” brand, with a six inch stroke.